I also did this drawing to try out a principle from Andrew Loomis’ “Fun With a Pencil” (a nearly 80-year old book available for free here), which is why she has that big `ol ugly shadow behind her.
In the book, Loomis diagrams how to determine the shadow position by triangulating the direction of light and angle of light.
I decided she’d be standing with a street lamp in front of her; as you can see I even drew the lamp it on a separate sheet of paper!
I’m not entirely certain I got it right; it looks weird. But maybe I just put my light source where no sane artist would.